Looking for the meaning or definition of the word atheist? Here's what it means.
Noun
A person who does not believe in deities.
(narrowly) A person who believes that no deities exist (especially, one who has no other religious belief).
(broadly) A person who rejects belief that any deities exist (whether or not that person believes that deities do not exist).
(loosely) A person who has no belief in any deities, such as a person who has no concept of deities.
(uncommon) A person who does not believe in a particular deity (or any deity in a particular pantheon), notwithstanding that they may believe in another deity.